Behavior Modeling and Scenario Authoring
for Virtual Environments

Project Overview

Our research lies in the broad domain of scenario control for dynamic virtual environments. This body of work focuses on methods to create realistic behaviors for simulated agents populating virtual environments and to adaptively manage the environment so that human subjects experience an orderly progression of events. For example, a virtual environment for training emergency room physicians or air traffic controllers might involve a series of situations where the succession of circumstances is based on a student's decisions, responses, and actions in the virtual environment.

Virtual environments present what appear to be conflicting demands on scenario control. On one hand, computer generated agents must behave in consistent and believable ways in a complex, dynamic environment. They must interact with other simulated agents and subjects who have considerable freedom of action. On the other hand, experimental and training applications require that subjects be tested under controlled conditions. The essential aspects of events and situations must be repeated from trial to trial. The challenge we face is to create scenarios that reproduce the intended conditions without overly restricting the subject's actions and while maintaining dynamism, complexity, and spontaneity in agent behaviors.

For example, consider the problem of creating a crash threat on a simulated urban freeway for a virtual driving environment. Such a scenario might be part of an experiment to determine the influence of Alzheimer's disease on the driving ability. The scenario requires generation of dense traffic that provides a backdrop for a critical situation such as an abrupt stop or dangerous lane change. In order to compare the performance of subjects, the behavior of the vehicles surrounding the driver must be carefully orchestrated -- some vehicle, possibly determined on-line, must perform the threatening deed and gaps in the traffic that provide possible escape routes must be consistently presented. Moreover, this coordination must be done inconspicuously so as not to alert subjects to the upcoming event.

Our research in this area encompasses technology for:

An important component of this research is the development of effective interfaces for authoring scenarios. This includes the design of basic behaviors, the specification of ambient characteristics of the environment, and the specification of critical events in the context of the scene in which they will take place.